Addition agent for motor fuels



Jan. 30, 1945. R. L.. MATHlAsEN ADDITION AGENT FOR MOTOR FUELS FiledJuly 30 194].

| IVI l llll illlln i MMUWM B5 Patented Jan. 30, 1945 2,368,482 t yADDITION AGENT Fon MoTon FUELS Roy L. Mathiasen, Perth Amboy, N. J.,assignor to Standard Oil Development Company, a corporation of Delawaref Application July 30, 1941, Serial No. 404,577

2 Claims.v (Cl. 196-150) This inventidn relai-.es to an improvedaddition agent for motor fuels and to the method for preparing the sameand is.'l more particularly concerned with an improved "solvent o At thepresent time it is customary to add small amounts of a substance calleda solvent oil to motor fuels for use ininternal combustion en` gines.The principal purpose of this solvent oil is to keep gummy or`gum-.forming constituents present in most motor fuels in a fluidcondition so that said gummy materials will not accumulate on thevalves, valve stems and other internal parts of the motor. The solventoil,'while dissolved in the motor fuel, is not intended to be burned inthe motor along with the fuel but should be sufficiently high-boiling sothat it will remain behind in the motor to act as an uppercylinderlubricant. It should of course be added only in very small amounts so asto affect `as little as possible the volatility and other importantcharacteristics of the motor fuel.

The material .ordinarily used as a solvent oil is a light naphtheniclubricating oil derived from coastal or Colombian crudes. It has a`Saybolt viscosity at 100 F. of about 1'00 seconds, and is characterizedby a high Kauri-butanol value, and a high solvent power for the gummyconstituents of motor fuels. It has a boiling range from about 400 to850 F. and is added in amounts of between about 0.1 and 1.0% by volumewhich are suiiicient to accomplish the desired purpose without otherwiseaffecting the performance of the motor fuel.

I have now found that the high boiling polymers formed when a naphtha ora hydrocarbon oil consisting essentially of hydrocarbons boiling in thegasoline range is subjected to catalytic reforming in the presence ofsubstantial quantities of added or recirculated hydrogen provide anexcellent material for use as a solvent oil. These high boiling polymersare ordinarily removed from the reformed product because o! their low A.P. I. gravity and high boiling point. They are characterized by high,octane number, high aromaticity and extremely high solventpower forgummy constituents and in addition act to inhibit the formation of gummyconstituents. .I have found that these polymers are always characterizedby high aromaticity no matter what may be the chemical characteristicsof the initial feed stock subjected to catalytic reforming in thepresence of hydrogen. The end-point of the initial feed stock determinesto a large extent the boihng range of the heavy polymers obtained sothat it can readily be yseenv that by regulating the end point of theinitial feed stock to catalyticreformingin the presence of hydrogen,

polymers of different boiling ranges may be obtained. l

The method by which the heavy polymers to be used as solvent oilaccording to the present invention are prepared will be fully understoodfrom the following description when read with reference to theaccompanying drawing which is a semi-diagrammatic view in sectionalelevation of one type of apparatus suitable for the purpose.

Referring to the drawing, numeral l designates a supply tank of ahydrocarbon oil consisting essentially of hydrocarbons boiling in thegasobefore it passes through the heating means. It

line range. vThis hydrocarbon oil may have been obtained from any sourceand itis immaterial whether it is vpredominately parafllnic, olefinic,

vnaphthenic or aromatic in character. The exact endpointoftheiiydrocarbon oil may be selected according to the boilingrange of the polymers which it is desired to obtain, as Vpointed outabove. 4

will be understood that the oil and hydrogen may, however, be heatedseparately if desired. The heated mixture of oil and hydrogen flows fromheating means 5 through line I0 into a reaction chamber I I whichcontains a catalytic ma- .terial l2 which promotes reforming.

Reaction chamber Il'is maintained at a temperature between 850 and 1050"F. and under a pressure between slightly above atmospheric and about 500pounds per square inch. The oil is passed through the reaction chamberat a rate' between 0.3 and 5.0 volumes of liquid oil per volume ofcatalyst per hour and is accompanied through the reaction chamber byfrom 1000 to 4000 cubic feet per barrel of oil of a gas containa ingbetween 30 and 90 mol percent of free hydrogen. The larger volumes ofgas will be used with the lower concentrations of free hydrogen thereinand vice versa. The catalyst I2 may be selected from a wide variety ofdifferent matei alumina gel or peptized alumina gel and from 1 to 20% byweight of molybdenum oxide or chromium oxide.

Products of reaction leave reaction chamber II through line I3, pass`through a cooling means Il and discharge into a separating means I5wherein gaseous and liquid products are separated. Ihe gaseous productsof reaction which will consist essentially of hydrogen and will containsmall amounts of low molecular weight hydrocarbons such as methane,ethane and propane are removed from separating means I5 through line I 6and may be recycled directly to line 9 by means of booster compressor I1or may be returned to tank 6 through lines I6 and I8. In some cases,particularly when the quantity of hydrocarbons in the gaseous productsis relatively high, it is desirable to pass the gaseous products beforebeing recycled through a scrubbing means denoted by the letter S whichis adapted to separate gaseous hydrocarbons from hydrogen.

The liquid products of reaction are removed from separating means I 5.through line I 9 and introducedinto a stabilizing means wherefrom thehydrocarbons which are too volatile for inclusion in gasoline areremoved through line 2| and passed to the renery fuel line or otherwisedisposed of. The remainder of the liquid products is removed fromstabilizing means 2t! through line 22 and introduced into afractionating or rerun tower 23. A fraction boiling in the rangeof-gasoline is removed from the rerun tower 23 through line 2d andcollected in a tank 25. The heavy polymers, comprising thosehydrocarbons boiling above the range of gasoline, are removed from reruntower 23 through line 26 and collected v in a tank 21. These polymerswill ordinarily conwill depend largely upon the maximum permissible endpoint of the motor fuel. It is preferable in many cases to segregatefrom the polymers a fraction eboiling between about 400 and 850 F. in

order to eliminate the (very high boiling materials which may cause gumformation and raise the end point of the motor fuel to an unduly largeextent.

Inasmuch as the process rby which the polymers are prepared also resultsin the production of al motor fuel of high octane number and otherdesirable characteristics, it'is advantageous to allow .the heavypolymers formed in said process to remain in the product to act assolvent oil. In this way the rerunning of the product may be eliminated,thus appreciably reducing the cost of operation. When it is desired toallow the polymers to remain in the gasoline produced by catalyticreforming in the presence of hydrogen the products removed fromstabilizing tower 20 -through line 22, instead of being forwarded torerun tower 2l, may be passed through line 22a and collected in a tank28. f

It will be understood that when the polymers are to be allowed to remainin the products of catalytic reforming, the end point of the feed stockto the catalytic reforming may beso a'djusted that the quantity andboiling range of the polymers produced will be such as to produce afinal product of the required end point. 0n the other hand, if it isfound thatl the quantity of polymers and the boiling range thereofexceed the required limits, the iinal product containing said polymersmay be blended with a 'suiiicient quantity of another gasoline notcontaining polymers so that the blend will contain the required amount.

In the operation of the process it will be found that the catalyst I2gradually loses its activity in promoting the desired reactions becauseof the formation or deposition thereon of carbonaceous contaminants suchas coke. The catalyst I2 will therefore require periodic regeneration torestore its activity. Regeneration of the catalyst may be accomplishedin any convenient manner, for example by passing hot, inert gasescontaining regulated small quantities of air or oxygen over the catalystmass to cause combustion of the carbonaceous contaminants. Because ofthe requirement for periodic regeneration of the catalyst, it isfrequently desirable to provide two 0r more reaction chambers similar toreaction chamber 4I IY so that while thecatalyst in one reaction chamberis undergoing regeneration, the iiow of oil and hydrogen may be divertedto another reaction chamber containingl fresh or freshly regeneratedcatalyst.

As pointed out above, the catalytic reforming is conducted in thepresence of hydrogen for a time and under such conditions that there isno overall net consumption of free hydrogen therein and there ispreferably an overall net production of free hydrogen. For this reason,it is possible to operate the process without the continuous addi.- tionof hydrogen from an extranec. .s source because the hydrogen or gasescontaining the same may be continuously recirculated.

It will be understood that many modifications may be made in theoperation of thel process. For example, instead of using catalyst in axed or stationary form, as illustrated in the drawing, the catalyst maybe used in nely divided or powdered form suspended in the oil vaporsandv hydrogen. One particularly advantageous type of operation with apowdered` catalyst is that in which the catalyst is used in what may becalled uid form in which the suspension of catalyst in vapors behaves inmuch the same way as a fluid. When powdered catalyst is used it will beunderstood that the regeneration thereof cannot be in situ but must beeffected outside the reaction chamber in a separate vessel.

The following examples illustrate the application of the invention:

Exam/ple 1 Initial boiling point, F.- -.f. 288 52% oil' F s 302 Gravity,A. P. I 30.4 Army octane No 99.8

This polymer is a highly satisfactory solvent oil for a. 400 F. endpoint gasoline.

Example 2..

A heavy naphtha having an end point of 419 F. and derived from a WestTexas crude is subject-.ed to catalytic reforming in 'the presence crhydrogen. The polymer fraction obtained from the product has the:following characteristics:

Gravity, A. P. I 7.4 Aniline point, "F -70 Sulfur, y 0.11 Refractiveindex 20 C 1.6117 Initial boiling point. "Ii 427 50% off F -n 555 84%oil "F 760 This polymer, while boiling above the gasoline range, is ahighly satisfactory solvent oil when blended in small amounts, less than1%, with a. gasoline.

This invention is not limited by any theories o1' the .mechanism of thereactions nor by any details which have been given merely for purposesof illustration but is limited only in and by the following claims inwhich it is intended to claim all novelty inherent in the invention.

I claim: Y l 1. An improved motor fuel comprising gasoline containing0.1 to 1% of the high boiling polymers produced in thecatalytic'reforming in the presence of hydrogen of a. hydrocarbon oilboiling in the gasoline rangeww'lich polymers are char- 'of 1,6117 and aboiling range between 400 and `ROY L. MATHIASEN.

